Industrial grinding machines of the type used to finish bearing races, valve lifter bodies, and other such mass-produced components are typically highly automated and must perform such operations as feed and wheel dress in a repetitive and precise fashion. Satisfactory precision and economy are difficult to achieve within the framework of prior art systems such as those involving slides or ways, and screw shafts or similar devices on crossing axes to effect both longitudinal and lateral feed. A radically different and much more workable approach to accomplishing feed is to mount either the wheelhead or the workhead on a slidebar which permits not only longitudinal displacement between the work and the wheel but pivotal displacement of one of the assemblies about the slidebar to effect a lateral feed motion. In this case, the lateral feed motion is not linearly but rather is along an arc related to the radial distance of the wheelhead center from the slidebar center. Such implementation is disclosed in the copending application for U.S. Pat. Ser. No. 464,917, filed Apr. 29, 1974, in the name of Hugh T. Edgar et al., now U.S. Pat. No. 3,932,960 issued Jan. 20, 1976. This invention also employs a slidebar and assemblies mounted thereon for both longitudinal and pivotal motion to produce a feed motion between work and wheel in a precise, repeatable fashion.
The dress operation must also be carried out with precision since dressing the wheel generally involves reducing the size thereof. Moreover, it is necessary to correlate the size reduction with the grind/feed operation to compensate for the change in wheel size. In prior art machines, the separate and independent control of dress and feed operations tends to compound the opportunity for mechanical position error; i.e., position errors due to metal compliance, play between contacting surfaces, and so forth.